Filter holding frames, such as Type 8 holding frames, may be used with a variety of fasteners, which will allow the installation of various combinations of ASHRAE prefiltration and final filtration into a ventilation system. Type 8 holding frames are available from Camfil Farr, Inc., of Riverdale, N.J. The installation may include any, or combinations of the following:                Any 1″ deep panel or pleated filter        Any 2″ deep panel or pleated filter        Any 4″ deep panel or pleated filter        Any 6″ or 12″ deep rigid filter        Any headered style rigid or pocket filter        
In contrast, high efficiency filters, such as 95% DOP filter, HEPA filters and higher efficiency filters, require the use of some type of mechanical clamping mechanism to effectively seal the filter to the filter housing and ensure that any bypass or leakage around that seal is no greater than the maximum penetration of the filter. For example, a HEPA filter with an efficiency of 99.97% has a maximum allowable penetration of 0.03%. Thus, the filter must seal to the filter housing effectively enough so that only a maximum of 0.03% leakage occurs between the filter and the holding frame.
The need to have clamping devices to seal high efficiency filters and various types of fasteners to secure and hold ASHRAE filters results in a very time consuming and costly process when filters must be removed and/or installed. This is particularly true on large filtration systems where dozens, if not hundreds, of filters must be removed and replaced on a regular basis. The use of wrenches, ratchets, or other types of tools is often required in order to loosen nuts, bolts, or other fasteners in order to remove the filters from the holding frames or to loosen the filter clamping mechanisms.
Thus, there is a need for a filter holding frame with a clamping mechanism that does not require the use of tools to operate, that can be used to effectively secure and seal high efficiency filters in a filter housing, while at the same time effectively hold and seal prefilters and lower efficiency filters in the holding frame.